1. Field
The following description relates to a semiconductor device. The following description also relates to an ultrahigh voltage resistor and the manufacturing method thereof, including a semiconductor device forming an insulator with a predetermined thickness between a resistor of polysilicon and a well region to apply ultrahigh voltage with a small sized resistor.
2. Description of Related Art
A semiconductor device includes a memory cell array region and a periphery region. The memory cell array region is formed to have a plurality of memory cells to store data. The periphery region is formed to have circuit devices including a power supply circuit including a resistor, a memory cell program, and a control circuit to control deletion and access operation.
A resistor among the circuit devices formed on the periphery region is important in circuit operation of the semiconductor device. The resistor is formed using at least one metal line in a metal layer, which may include a junction resistor, a poly resistor and a metal resistor. Such a junction resistor is temperature sensitive, with a small width, and thereby has a huge change in resistor value. Moreover, a metal resistor has a difficulty in including a resistor with high resistor value because of its low resistor value. Thereby, a poly resistor with a small change in temperature and voltage is better for use in producing a resistor with high resistor value.
Generally, a high voltage resistor using a poly resistor uses a voltage distribution method using a plurality of unit resistors to provide a high breakdown voltage feature. In other words, a high voltage resistor is potentially formed by linking several low voltage unit resistors.
Generally, a unit resistor includes a well region formed on a semiconductor substrate, an oxide layer formed on the well region, and a polysilicon layer formed on the insulating layer. Moreover, two terminals are formed on a polysilicon layer, wherein each terminal is used as a terminal supplied with a power voltage or a ground terminal. Alternatively, each terminal is linked with a neighboring resistor of different unit for voltage distribution.
Generally, two unit resistors are used when forming a high voltage resistor using the unit resistors, for example, to form a 400V resistor. In other words, each resistor supplies resistance to 200V, respectively, and a well region including each unit resistor applies bias.
Thereby, a resistor with relatively high voltage feature is potentially formed on a semiconductor device.
However, a high voltage resistor structure using each unit resistor as aforementioned presents the following issues.
When a voltage that is higher than the aforementioned 400V is applied, a resistor is formed with another well region added accordingly, because a voltage distribution method is used. In this case, there is an issue of a size increase of a semiconductor substrate and semiconductor device increases as well because a well region is added.
Moreover, since bias is required to be applied on a well region of a unit resistor, a circuit component for providing bias is also additionally required.
Likewise, since semiconductor device development difficulty increases due to a requirement of circuit features as discussed to apply a bias on a well region, research development to make size of an equipment with a semiconductor device becomes more difficult.